Under the No Child Left Behind (NCLB) Act, every school is subject to the controversial mandates for annual test score gains contained in the federal law. The law represents a profound change in the relationship between the federal government and state and local education agencies regarding who controls education and has direct implications for what happens educationally in schools and classrooms. Although NCLB affects these and other important areas of the educational system and imposes great pressure on school leaders, it is silent on the role of principals in fostering school improvement. This article examines the provisions of the law which have important implications for principals. It discusses the results of a survey aimed at understanding teachers' views of the assumptions underlying NCLB and their implications for principals. It concludes that principals should play a role in explaining to communities, the media, and policymakers some of the contradictions and oversimplifications in the existing law and what would be needed in order to be able to make real progress toward NCLB's worthy goals.